Two former Parramatta Eels players are accused of harbouring semi-automatic weapons and possessing more than half-a-million dollars in cash after dramatic arrests in Sydney's Centennial Park yesterday.

Six Victorian shootings in four days

Two men have walked into separate hospitals with gunshot wounds as Victoria deals with six shootings in four days.

Police are looking interstate at laws that crack down on these types of shootings, which detectives say are acts of revenge.

"All of those shootings have involved offenders who are known to their victims, and from what we know at this time, they are all related to retribution or payback," acting commander Peter De Santo told reporters on Monday.

A 23-year-old Caroline Springs man with a gunshot wound drove himself on Monday morning to the Mercy Hospital in Werribee, where he is refusing to co-operate with police.

Detectives believe his shooting, at a Caltex station in Werribee, is linked to a shooting incident at a cannabis crop house in St Albans later on Monday.

On Sunday night, a 25-year-old member of the Mongols outlaw motorcycle gang was driven to the Sunshine Hospital with a gunshot wound.

The man also refused to co-operate with police, who allegedly found a commercial quantity of ecstasy in the car he arrived at the hospital in.